1. Field of the Invention
The present invention relates to travel control device and method for vehicles for causing unmanned vehicles, which are equipped with travel control means for moving the vehicles along a directed traveling course according to the data of the traveling course, to proceed towards each other from the opposite directions on a traveling road having adjacent outward/return traffic lanes.
2. Description of the Related Art
When conveying the earth and sand deposited in a quarry, mine, or other large work area, in order to avoid accidents caused by fatigue of a worker, to achieve downsizing of manpower, and to improve the productivity by extending the work hours, there is introduced an unmanned vehicle travel system for activating unmanned vehicles instead of manned vehicles such as off-road dump trucks. The unmanned vehicle travel system is constructed such that, in order to manage the operation of plural unmanned dump trucks, monitor stations are set up as ground-based stations and the plural unmanned dump tracks are integrally managed and monitored by means of these monitor stations.
However, it is practically impossible to make all vehicles traveling in the work area unmanned. Specifically, besides the unmanned dump trucks, it is necessary to allow manned vehicles such as a grader, road sprinkler, wheel loader, excavator, trailer, courtesy car for operator, measurement vehicle, and other manned vehicle to travel in the work area.
In the work area, as shown in FIG. 1, which is a schematic diagram showing an example of a road in a mine, inbound/outbound traffic lanes Ra, Rb which are adjacent to each other are provided on a traveling road R which connects a loading area A to a dumping area B, and, on the basis of data of the traveling course whish is set previously for each lane Ra, Rb (course data) and data related to travel of the vehicle which is obtained using a position measuring system such as a GPS (travel data: vehicle position, speed and the like), each vehicle T1, T2 is autonomously guided to travel, whereby the vehicles T1, T2 proceed towards each other from the opposite directions on the inbound/outbound traffic lanes Ra, Rb respectively.
Supposing, for example, that a manned motor grader T3 carries out a road construction on one side of the inbound/outbound traffic lanes, e.g. the traffic lane Ra, the road construction is performed at low speed or in a state in which the motor grader T3 is stopped, and thus impedes high-speed running of the vehicle T1 traveling behind on the same traffic lane Ra, thereby causing a reduction in the conveyance efficiency and work efficiency.
If the vehicles T1, T2, which proceed towards each other from the opposite directions, are both manned vehicles, the on-board operators can directly communicate with each other so that the vehicle T1 can pass the grader T3 and travel along a detour course Ca through the lane Rb which is opposite in relation to the vehicle T1, whereby the high-speed traveling can be continued without causing interference between the vehicles.
Furthermore, even if the vehicle T1, which tries to pass the grader T3 through the detour course Ca, is a manned vehicle and the opposing vehicle T2 is unmanned, the operator of the manned vehicle T1 can travel the detour course Ca with awareness about movement of the vehicle T2 on the opposite side, thus the high-speed traveling can be continued without causing interference between the vehicles.
Moreover, the operator of the manned vehicle T1 carefully observes movement of the grader T3 that the manned vehicle T1 tries to pass, and obtains permission to pass the grader T3, from the grader T3 via a wireless machine or the like according to need. Therefore, the manned vehicle T1 can pass the grader T3 without causing interference with the grader T3, while preventing a surprising behavior of the grader T3 (when, for example, the grader T3 strays onto the opposite lane Rb to make a turn).
However, in the case in which the vehicle T1, which tries to pass the grader T3 through the detour course Ca, is an unmanned vehicle (in the case in which the vehicle T2 on the opposite side is an unmanned or manned vehicle), the unmanned vehicle T1 itself does not have the ability to travel the opposite side along the detour course Ca while carefully observing movement of the vehicle T2 on the opposite side, or the ability to obtain permission to pass from the operator. Therefore, it is impossible for the vehicles to continue high-speed traveling without causing interference between the vehicles, unless some sort of control is added thereto. Further, the unmanned vehicle T1 itself does not have the ability to pass the grader T3 along the detour course Ca while carefully observing movement of the grader T3 that the unmanned vehicle T1 tries to pass. Therefore, interference with the grader T3 may be caused because of a surprising behavior of the grader T3 (when, for example, the grader T3 strays onto the opposite lane Rb to make a turn) while passing the grader T3, unless some sort of control is added to the vehicle T1.
Japanese Patent Application Publication No. 2000-339029 describes the invention which is designed to prevent the occurrence of interference between vehicles, wherein a circle, whose radius is the distance in which a vehicle moves from a current position thereof at the maximum speed, is obtained for each vehicle as an existable area, on the basis of the current position of each vehicle and the maximum speed of each vehicle, and, when interference is caused between the existable areas, it is determined that the corresponding vehicles could interfere with each other, whereby one of the vehicles is decelerated or stopped.
Also, Japanese Patent Application Publication No. H9-231500 describes the invention which is designed to prevent the occurrence of interference between an unmanned vehicle and manned vehicle that approach each other when traveling in the same direction, in the case in which the both vehicles fleet in the same direction, wherein when the distance between the manned vehicle and the unmanned vehicle behind narrows to a predetermined distance or less, the unmanned vehicle behind is decelerated or stopped.
Also, Japanese Patent Application Publication No. H11-242520 describes the invention which is designed to prevent the occurrence of interference between a vehicle and an obstacle on a traveling road, wherein a video camera or other obstacle sensor is installed in the vehicle, and when an obstacle is detected on the traveling road by the obstacle sensor, a detour course is created on the basis of information detected by the obstacle sensor, so that the vehicle is allowed to travel along the detour course to skirt the obstacle.
According to the invention described in Japanese Patent Application Publication No. 2000-339029, since one of the vehicles is decelerated or stopped when the vehicles come close to each other, the occurrence of interference between the vehicles can be prevented securely.
However, when the above invention is applied to a circumstance where the vehicle T1 is caused to travel along the detour course Ca and pass the grader T3 as shown in FIG. 1, the vehicle T1 comes close to the grader T3 as the vehicle T1 passes the grader T3, and thus the T1 is decelerated or stopped. Consequently, passing the grader T3 cannot be achieved. Moreover, in the above invention, coordination between the vehicles that proceed towards each other from the opposite directions is not taken in consideration at all. For this reason, there may be generated a situation in which the vehicle T1, which is in the middle of traveling the opposite lane Rb along the detour course Ca, comes close to the vehicle T2 traveling the same lane Rb in the opposite direction. In this case, the vehicle T1 is decelerated or stopped because the vehicle T1 comes close to the vehicle T2, thus even if the occurrence of interference between the both vehicles proceeding towards each other from the opposite directions can be prevented, passing the grader T3 cannot be achieved.
The invention described in Japanese Patent Application Publication No. H9-231500 is based on only the case in which plural vehicles fleet in the same travel direction, and does not assume the case in which plural vehicles proceed towards each other from the opposite directions. Therefore, when the above invention is applied to a circumstance where the vehicle T1 is caused to travel along the detour course Ca and pass the grader T3 as shown in FIG. 1, the vehicle T1 is decelerated or stopped at the point of time when the vehicle T1 comes close to the grader T3 to a predetermined distance in order to pass the grader T3, thus passing the grader T3 cannot be achieved.
The invention described in Japanese Patent Application Publication No. H11-242520 is based on only the case of avoiding an obstacle placed on a traveling road, and the vehicles proceeding towards each other from the opposite directions are not taken into consideration at all. For this reason, as shown in FIG. 1, even if the vehicle T1 can be caused to travel along the detour course Ca and pass the grader T3, the vehicle T1 may interfere with the vehicle T2 which travels on the opposite side. Moreover, in the invention described in Japanese Patent Application Publication No. H11-242520, the detour course Ca is created based on the information detected by the obstacle sensor, and a future behavior of the grader T3 which is the obstacle is not taken into consideration at all. Therefore, because of a surprising behavior of the grader T3, the vehicle T1 may interfere with the grader T3 while passing the grader T3 (when, for example the grader T3 strays onto the opposite lane Rb to make a turn). Also, the present invention cannot cope with a circumstance where there is a place which is slippery because of rain or where there is an object which should be avoided but could not be detected by the obstacle sensor.
Furthermore, the traveling road R such as a mine is an unpaved road, and a road surface thereof has windrow formed by a road maintenance work performed by the grader T3, or other obstacles that obstruct travel of the vehicle T1. Therefore, in some cases, there occurs a problem in which the vehicle T1 runs on to the windrow when passing the grader T3.
As described above, in any of the conventional technologies described above, although the occurrence of interference between vehicles can be prevented, passing a vehicle at high speed cannot be achieved, or although passing a vehicle at high speed can be achieved, the occurrence of interference between vehicles cannot be prevented, thus the conventional technologies could not satisfy such cases.